ArticlePDF Available

Low, moderate, or high protein yogurt snacks on appetite control and subsequent eating in healthy women

Authors:
Research report
Low, moderate, or high protein yogurt snacks on appetite control and
subsequent eating in healthy women
Steve M. Douglas
a
, Laura C. Ortinau
a
, Heather A. Hoertel
a
, Heather J. Leidy
a,b,
a
University of Missouri, Dept. of Nutrition, 204 Gwynn Hall, Columbia, MO 65201, United States
b
Dept. of Nutrition & Exercise Physiology, School of Medicine, 204 Gwynn Hall, University of Missouri, Columbia, MO 65211, United States
article info
Article history:
Received 28 May 2012
Received in revised form 29 August 2012
Accepted 16 September 2012
Available online 25 September 2012
Keywords:
Snacking
High protein
Yogurt
Appetite
Satiety
abstract
This study assessed whether afternoon snacks, varying in protein content, influence appetite-control and
eating initiation. Fifteen healthy women (age: 26 ± 2 y) randomly consumed 160 kcal afternoon yogurt
snacks containing Low (LP), Moderate (MP), or High (HP) protein (5,14, 24 g protein, respectively) or
had no snack (NS) for 3 days. On day 4, the volunteers came to our facility to consume a standardized
lunch. The respective snack pattern was completed 3 h post-lunch. Perceived sensations were measured
every 30 min until dinner was voluntarily requested. An ad libitum dinner was then provided. Snacking,
regardless of protein content, led to reduced hunger and increased fullness, which were sustained up to
120 min post-snack vs. NS (all, p< 0.05). Between snacks, hunger was lower and fullness was higher
throughout post-snack following HP vs. LP (p< 0.05). Snacking delayed the onset of eating vs. NS (all,
p< 0.05). Specifically, dinner was requested at 124 ± 7 min following NS, 152 ± 7 min with LP,
158 ± 7 min following MP, and 178 ± 7 min post-snack for HP. Between snacks, HP led to the latest
request time vs. LP (p< 0.001) and MP (p< 0.05). Although the energy content consumed at dinner
was lower following the yogurt snacks vs. NS, the 160 kcal snacks were not fully compensated for at this
meal. In conclusion, an afternoon snack of Greek yogurt, containing 24 g protein, led to reduced hunger,
increased fullness, and delayed subsequent eating compared to lower protein snacks in healthy women.
Ó2012 Elsevier Ltd. All rights reserved.
Introduction
Modest increases in dietary protein have become part of suc-
cessful, dietary strategies for weight loss, as well as, the prevention
of weight re-gain following weight loss (Leidy & Carnell et al.,
2007; Westerterp-Plantenga et al., 2009). One key factor in the
effectiveness of higher protein diets, compared to high fat and/or
high carbohydrate versions, is the observed improvements in
appetite control and satiety (Leidy & Carnell et al., 2007; Wester-
terp-Plantenga et al., 2009). Most of the additional protein in these
diets is incorporated into meals containing anywhere from 28 g
protein/meal to well over 100 g protein/meal (Leidy & Carnell
et al., 2007; Westerterp-Plantenga et al., 2009). Although these
meals elicit significant reductions in appetite and increases in
satiety, it is unclear as to whether smaller quantities of protein,
consumed as afternoon snacks, elicit similar benefits.
Some of the more commonly consumed higher-protein snacks
in the US include dairy products such as milk, cheese, and yogurt
which usually contain between 8 and 14 g of protein/serving (Pier-
nas & Popkin, 2010). In a recent article by Dougkas et al. (Dougkas
et al., 2012), isocaloric (i.e., 200 kcal) morning, dairy snacks con-
taining an average of 12 g of protein led to reduced appetite and
lunch intake compared to no morning snack. Furthermore, greater
reductions in appetite were observed with the yogurt snack com-
pared to the cheese and milk snacks (Dougkas et al., 2012). Since
many have speculated that the majority of snacking in the United
States occurs in the afternoon and evening, rather than the morn-
ing (Stachura, 2010), we recently completed a study that extends
these findings to examine the effects of consuming afternoon yo-
gurt snacks containing normal (5 g protein) vs. increased protein
(14 g protein) on appetite control and satiety (Ortinau, Culp,
et al., 2012). We also incorporated a more accurate assessment of
satiety by allowing the participants to voluntarily request dinner
based on motivational state/drive to initiate eating (Marmonier,
Chapelot, et al., 2000; Ortinau et al., 2012). Regardless of protein
content, both yogurt snacks equivalently reduced hunger, in-
creased fullness, and delayed the onset of eating compared to no
snack (Ortinau et al., 2012). However, no differences were found
between yogurts, suggesting that additional protein (P14 g) is re-
quired to elicit protein-related benefits on appetite control and
satiety (Ortinau et al., 2012).
In 2008, Greek yogurt was introduced into the United States
with sales increasing exponentially over the past several years
(The Nielsen Company, 2010). The increased frequency of
0195-6663/$ - see front matter Ó2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.appet.2012.09.012
Corresponding author.
E-mail address: leidyh@missouri.edu (H.J. Leidy).
Appetite 60 (2013) 117–122
Contents lists available at SciVerse ScienceDirect
Appetite
journal homepage: www.elsevier.com/locate/appet
consumption, along with the increased protein content of Greek
yogurt (20–24 g/serving) (USDA, 2011), which is almost 5 times
that of regular yogurt, make this a potentially ideal snack option.
The purpose of this study was to assess whether the consump-
tion of afternoon yogurt snacks, varying in protein content from 5
to 24 g protein, influence afternoon appetite and satiety responses
and delay the onset of eating. As discussed above, eating initiation
(i.e., the onset of eating) has been previously validated and utilized
in other snack studies as an excellent, novel indicator of motiva-
tional drive to eat and ‘‘satiety power’’ (Himaya, Fantino, et al.,
1997; Marmonier et al., 2000).
Methods
Participants
Healthy, pre-menopausal women chose to participate in this
study by responding to flyers posted on the University of Missouri
(MU), Columbia campus or through the MU-listserv. Eligibility in-
cluded the following: (1) age 18–50 y; (2) normal to overweight
(BMI between 18 and 27 kg/m
2
); (3) no metabolic diseases/condi-
tions; (4) not been clinically diagnosed with an eating disorder; (5)
not currently on a weight loss or other special diet (in the past
6 months); (6) not a smoker (in the past year); (7) habitually eat
(i.e., at least 5 times/wk) breakfast between 7:00 and 9:00 am,
lunch between 11:00 am and 1:00 pm, an afternoon snack between
2:00 and 4:00 pm, and dinner; (8) no food allergies or intolerances
to dairy products; (9) and rated the overall liking of the study
snack foods higher than ‘‘Neither Like nor Dislike’’ on the screening
palatability questionnaire.
Twenty-two participants began the study. Of these, 15 (age:
26 ± 2 y; BMI: 22.3 ± 0.5 kg/m
2
) completed all study procedures.
Of those that did not complete the study, seven had unusable per-
ceived appetite and satiety responses due to computer program-
ming errors. All participants were informed of the study
objectives, procedures, and risk. Written informed consent was ob-
tained from all participants. The study was approved by the MU
Human Subjects’ Institutional Review Board. The participants re-
ceived $300 for completing all study procedures.
Experimental design/study procedures
The study incorporated a randomized crossover design compar-
ing the consumption of 160 kcal afternoon yogurt snacks contain-
ing Low Protein (LP, 5 g protein), Moderate Protein (MP, 14 g
protein), and High Protein (HP, 24 g protein) vs. no snacking (NS).
Prior to the start of the study, the participants were asked to
document their habitual breakfast, lunch, and afternoon snack
times. The snack patterns and associated testing days were
scheduled so that each participant consumed the afternoon snack
(or refrained from snacking) 3 h after lunch; however, the time
of day when this occurred was based on the participant’s previous,
habitual snack time. Once this was determined, the participants
were acclimated to each snack pattern for 3 consecutive days. Dur-
ing the acclimation days, the participants simply refrained from
eating a snack (i.e., NS) or consumed 1 of the 3 study yogurt snacks
provided. Four ounces of water was also consumed at this time.
On day 4 of each pattern, the participants consumed a standard-
ized breakfast, at home, and reported to the MU Brain Imaging
Center 1 h prior to lunch to begin the 8 h testing day (Fig. 1). Each
volunteer was placed in a comfortable room, absent of time cues.
The room contained a recliner, workstation, and laptop computer
for the participants to use, at leisure, throughout the day. The test-
ing day began with the consumption of the standardized lunch
meal. The respective snack pattern was completed 3 h after lunch.
This included the 160 kcal snack (or no snack) and 8 oz of water.
Perceived appetite and satiety questionnaires were completed
every 30 min throughout the remainder of the day. When the par-
ticipant requested to eat again, an ad libitum dinner was provided.
Regardless of time of dinner request, the volunteers were required
to remain in the facility until the full 8 h testing day was
completed.
Snacks
The dietary characteristics of the snacks are shown in Table 1.
All yogurt snacks were commonly consumed, commercially avail-
able products, similar in energy content and varying in protein
quantity. Specifically, the LP yogurt was 14% protein, 76% CHO,
and 10% fat; the MP yogurt was 36% protein, 64% CHO, and 0%
fat; and, the HP yogurt contained 60% protein, 40% CHO, and 0%
fat. To control for energy content and to examine commercial prod-
ucts, energy density, dietary fat, sugar, and fiber were not held
constant.
The sensory properties (i.e., aroma, flavor, texture, and overall
liking (palatability)) of each snack were assessed using a comput-
erized 100 mm VAS scale questionnaire during screening and after
the first and last bite of each snack during the acclimation and test-
ing days (Table 1). The questions are worded as ‘‘how strong is the’’
with anchors of ‘‘not all’’ to ‘‘extremely.’’ The Adaptive Visual Ana-
log Scale Software (Neurobehavioral Research Laboratory and
Clinic; San Antonio, TX) was used for these assessments.
Meals
During the morning of each testing day, a 300 kcal breakfast
meal was provided. The breakfast consisted of a breakfast quesa-
dilla and fruit. The macronutrient composition of the breakfast
Fig. 1. Diagram illustrating the 8 h testing day procedures.
118 S.M. Douglas et al. / Appetite 60 (2013) 117–122
was 15% protein, 60% CHO, and 25% fat. The participants consumed
this at home within 1 h after waking (between 7:00 and 9:00 am).
The participants were instructed to return all wrappers associated
with the pack-out breakfast foods as well as any potential remains.
In addition, the participants also documented that each component
of the breakfast meal was consumed.
During each of the testing days, a 500 kcal lunch meal was pro-
vided. The lunch consisted of a sandwich, chips, and applesauce
and was consumed within 30 min. The macronutrient composition
of the lunch was 15% protein, 55% CHO, and 30% fat; 8 oz of water
was also provided.
The ad libitum dinner consisted of chicken parmesan pizza
pocket pieces. The participants were instructed to eat as much as
they desired until feeling ‘comfortably full’ within 30 min. Addi-
tional pizza pocket pieces were given to the participants as needed.
All contents were weighed before the meal and the remaining con-
tents were weighed after the meal to determine the amount con-
sumed. Total dinner energy intake and macronutrient
composition were then determined.
Appetite and satiety questionnaires
Computerized questionnaires, assessing perceived sensations of
hunger, fullness, desire to eat, and prospective food consumption,
were completed throughout the testing days. The questionnaires
contain visual analog scales incorporating a 100 mm horizontal
line rating scale for each response. The questions are worded as
‘‘how strong is your feeling of’’ with anchors of ‘‘not all’’ to ‘‘extre-
mely.’’ The Adaptive Visual Analog Scale Software (Neurobehavior-
al Research Laboratory and Clinic; San Antonio, TX) was used for
these assessments.
Time to voluntary dinner request
In addition to the perceived appetite and satiety questionnaires
completed every 30 min, the participants were also asked whether
they would like to request dinner. When the response was ‘‘Yes, I
want to eat dinner right now’’, the time from snack consumption
was recorded. The participants were permitted to request dinner
in between the 30 min intervals if desired.
Data and statistical analysis
A power analysis was performed prior to the start of the study
to identify appropriate sample size. The time to dinner request
from Marmonier et al. (Marmonier et al., 2000) was used for this
analysis. The 60 min delay in dinner request between the high pro-
tein snack vs. no snack led to an effect size of 1.03, indicating that a
sample size of n= 15 would provide >80% power to detect a differ-
ence between snacks.
Summary statistics (sample means, and sample standard devia-
tions) were computed for all data. Total area under the curve (AUC)
was calculated from the postprandial time points for the perceived
sensations. A repeated measures ANOVA was applied to compare
the main effects of snacking on the following outcomes: afternoon
appetite and satiety; time to dinner request; and subsequent food
intake (at dinner). When main effects were detected, post-hoc pair
wise comparisons were performed using Least Significant Differ-
ences to identify differences between snacks.
Since many of the snack components were, by design, not
matched, there were numerous dietary and sensory factors that
might have contributed to the overall treatment effects. To identify
covariates, Pearson correlational analyses were first performed on
perceived snack aroma, flavor, texture, appearance, and palatabil-
ity responses and our primary outcome, that being time to dinner
request. Flavor (r: 0.347, p< 0.05) and palatability (r: 0.345,
p< 0.05) were found to be significantly associated with time to
dinner request and were thus included as potential covariates
using a mixed factor ANOVA. Because neither factor was found to
act as a covariate with snack pattern, the data is reported as unad-
justed means.
Pearson correlational analyses were also performed to identify
associations between protein content of the afternoon snacks and
study outcomes.
Analyses were conducted using the Statistical Package for the
Social Sciences (SPSS; version 19.0; Chicago, IL, USA). p< 0.05
was considered statistically significant.
Results
Perceived appetite and satiety
Figure 2 illustrates the post-snack perceived hunger responses
until dinner was voluntarily requested. Regardless of protein con-
tent, all yogurt snacks led to immediate reductions in hunger
which were sustained up to 120 min post-snack vs. NS (all,
p< 0.05). Between yogurts, HP led to lower post-snack hunger at
30, 90, and 150 min vs. LP (all, p< 0.05) and tended to be lower
at 150 min vs. MP (p= 0.08). Regarding the 120 min AUC assess-
ments, all yogurt snacks led to lower 120 min hunger AUC vs. NS
Table 1
Snack characteristics.
No snacking (NS) Low protein yogurt (LP) Moderate protein yogurt (MP) Higher protein yogurt (HP)
Dietary components
Energy content (kcal) 160 160 160
Energy density (kcal/g) 0.94 ± 0 0.94 ± 0 0.66 ± 0
Viscosity (Pa s) 10.9 ± 0 38.4 ± 0 18.6 ± 0
Mass (g) 170 ± 0 170 ± 0 255 ± 0
Volume (ml) 170 ± 0 165 ± 0 250 ± 0
Total protein (g) 5 14 24 .0
Total carbohydrates (g) 30 .0 25 17
Sugar (g) 26 20 14
Fiber (g) 0 0 2.2
Total fat (g) 1.5 0 0
Sensory components
A,B
Aroma 75 ± 4 66 ± 4 74 ± 4
Flavor 79 ± 3
a,b
70 ± 4
b
81 ± 3
a
Texture 68 ± 6 70 ± 4 67 ± 6
Appearance 74 ± 4 68 ± 6 75 ± 5
Palatability (liking) 78 ± 5 73 ± 3 79 ± 3
A
Data collected during the ‘last bite’ of the afternoon snack.
B
Difference letters denote significance.
S.M. Douglas et al. / Appetite 60 (2013) 117–122 119
(all, p< 0.05). HP led to lower 120 min hunger AUC vs. LP (p< 0.05),
but not MP. No other differences were detected.
Figure 3 illustrates the post-snack perceived fullness responses
until dinner was voluntarily requested. Regardless of protein con-
tent, all yogurt snacks led to immediate increases in fullness which
were sustained up to 120 min post-snack vs. NS (all, p< 0.05). Be-
tween yogurts, HP led to greater post-snack fullness at 60, 90, and
150 min vs. LP (all, p< 0.05) and at 150 min vs. MP (p< 0.05). MP
led to greater fullness at 60 min vs. LP (p< 0.05) Regarding the
120 min AUC assessments, all yogurt snacks led to greater
120 min fullness AUC vs. NS (all, p< 0.05). HP led to greater
120 min fullness AUC vs. LP (p< 0.05), but not MP. No other differ-
ences were detected.
Eating initiation
Eating initiation, as determined by time to dinner request, is
shown in Fig. 4. No snacking led to the earliest dinner request, at
approximately 2 h post-snack; LP and MP yogurts led to a dinner
request 2½ h post-snack; and, HP led to the latest request 3 h
post-snack. Statistically, all yogurt snacks delayed the onset of
eating vs. NS (all, p< 0.05). Between snacks, HP led to the latest on-
set of eating vs. LP and MP (both, p< 0.05). No other differences
were detected.
Ad libitum dinner
During the ad libitum dinner, the participants consumed
807 ± 51 kcal following NS, 737 ± 48 kcal with MP, 730 ± 36 kcal
following HP, and 705 ± 43 kcal with LP. All yogurt snacks led to
fewer kcal consumed at dinner vs. NS albeit only significant be-
tween LP vs. NS. Although the energy content at dinner was lower
following the yogurt snacks vs. NS, the 160 kcal snack was not fully
compensated for at this meal. Specifically, the LP snack led to a sur-
plus of +60 kcal, the MP snack of +90 kcal, and the HP snack of
+83 kcal. No differences were found between yogurt snacks.
Snack protein content and study outcomes
The relationship between the protein content of the yogurt
snacks and study outcomes were identified through Pearson Corre-
lation analyses. Protein content of the yogurt snacks was inversely
Fig. 2. Perceived hunger assessed throughout the post-snack period with 120 min area under the curve (AUC) shown to the right of the line graphs.
No snack (NS) vs. All
snack, p< 0.05;
high protein (HP) vs. low protein (LP), p< 0.05;
à
HP vs. moderate protein (MP), p= 0.08.
Fig. 3. Perceived fullness assessed throughout the post-snack period with 120 min area under the curve (AUC) shown to the right of the line graphs.
No snack (NS) vs. All
snack, p< 0.05;
high protein (HP) vs. Low protein (LP), p< 0.05;
à
HP vs. moderate protein (MP), p< 0.05;
§
MP vs. LP, p< 0.05.
120 S.M. Douglas et al. / Appetite 60 (2013) 117–122
associated with post-snack hunger AUC (r:0.457, p< 0.001) and
positively associated with post-snack fullness AUC (r: 0.391,
p< 0.003) and time to dinner request (r: 0.535, p< 0.001).
Discussion
The consumption of a 160 kcal afternoon yogurt snacks, varying
in protein content, led to reduced afternoon hunger, increased full-
ness, and delayed the onset of eating. Additional benefits were
shown with the high protein snack containing 24 g of protein.
These data suggest that a small, high protein afternoon snack reg-
imen might delay or prevent subsequent snacking and over-eating
later in the day. Further research to critically test this hypothesis is
warranted.
Snacking is an increasingly common daily habit practiced
among nearly all (i.e., 97%) adult Americans and has closely mir-
rored the rise in obesity (Piernas & Popkin, 2010). Although snack-
ing is often triggered by physiological hunger, many people often
snack due to environmental stimuli such as TV ads, social events,
and snack availability or as a result of emotional and/or psycholog-
ical factors including boredom, reward/fun, and/or stress (Johnson
& Anderson, 2010; Sloan, 2009). Unfortunately, many of the com-
monly consumed snacks readily available are those which are
nutrient-poor yet energy dense foods including desserts, salty
snacks, and sugar-sweetened beverages (Piernas & Popkin, 2010).
To date, almost 30% of daily intake (700 kcal/d) is comprised of
these unhealthy, afternoon/evening snacks (Piernas & Popkin,
2010). It is currently unknown as to whether the frequency, size,
or quality of these snacks has the greatest influence on energy in-
take regulation and/or body weight management. However, cur-
rent trends indicate that Americans have an increased desire to
purchase and consume healthier snack options (Sloan, 2011). Since
yogurt is a good source of calcium and other vitamins and miner-
als, contains probiotics, and is higher in protein than most other
snacks, it is generally considered a healthy, nutritious snack. This
may, in part, explain the increased yogurt sales in the US (Sloan,
2011; Stachura, 2010).
The consumption of high protein foods, meals, and overall diets
have led to improved appetite control, satiety, reduced reward-
driven eating behavior, and reduced daily energy intake compared
to high CHO and/or high fat versions (Batterham, Heffron, et al.,
2006; Holt, Miller, et al., 1995; Leidy, Armstrong, et al., 2010; Leidy,
Lepping, et al., 2011; Leidy & Mattes et al., 2007; Marmonier et al.,
2000; Poppitt, Proctor, et al., 2011; Potier, Fromentin, et al., 2009;
Skov, Toubro, et al., 1999; Weigle, Breen, et al., 2005; Westerterp-
Plantenga et al., 2009). Although many of these studies incorporate
the additional dietary protein in larger meals containing quantities
of P28 g/eating occasion, a few protein-rich snack studies have
been completed.
In 2000, Marmonier et al. (Marmonier et al., 2000) compared
the consumption of 235 kcal afternoon snacks, varying in
macronutrients, on afternoon hunger, satiety, and the time at
which dinner was spontaneously requested. In general, snacking
led to reductions in afternoon hunger and increases in afternoon
fullness (satiety) compared to no snacking (Marmonier et al.,
2000). Although no differences in perceived sensations were ob-
served between snack types, the high protein (46 g protein) snack
led to a delay in the request for dinner compared to the high fat
and/or high CHO snacks (Marmonier et al., 2000).
In a more recent study (Poppitt et al., 2011), water beverages,
varying in protein quantities (i.e., 0–20 g) were consumed 2 h after
breakfast. In this study, perceived appetite and satiety were as-
sessed throughout the day. Additionally, the time during which
hunger and fullness returned to baseline were assessed. Increasing
the protein content in the water beverages led to reductions in
morning hunger and increased morning fullness. Furthermore,
hunger was suppressed and fullness was maintained longer when
the 20 g protein-rich water beverages were consumed compared to
plain water. Lastly, Potier et al. (2009) examined whether two dif-
ferent 200 kcal cheese ‘snacks’ containing 22 g protein would re-
duce subsequent meal (i.e., lunch) and daily energy intake. Both
high protein snacks led to reduced intake at lunch and over-com-
pensation of the snack throughout the remainder of the day. Unlike
many of these studies, we incorporated a commercially available,
commonly-consumed afternoon snack containing a modest
amount of protein (i.e., 24 g). Regardless of the experimental de-
sign differences, we also found reduced hunger, increased satiety,
and delayed onset of eating following the high protein yogurt vs.
no snack or consuming lower-protein yogurts. Additionally, we
also examined whether the 160 kcal afternoon snack would be
fully compensated for at the dinner meal. Similar to the findings
of Marmonier et al. (2000) and Potier et al. (2009), we also only
found partial compensation of the snack energy content at dinner,
with no differences between yogurt snacks. However, Potier et al.
(2009) also examined daily intake and found that the 200 kcal
(22 g protein) morning snack was actually over-compensated for
by the end of the day with compensation of approximately 132%
(i.e., 300 kcal/d less than when no snack is provided). Thus, it is
plausible that the high protein, afternoon yogurt snack provided
in our study might lead to similar compensatory eating behaviors
throughout the evening.
One of the more novel procedures incorporated in the current
study as well as other published studies (Cummings, Frayo, et al.,
2004; Marmonier et al., 2000) involved the use of voluntarily eat-
ing request. The majority of acute studies typically incorporate a
fixed-meal design in which the study participants are required to
eat at a set time, regardless of ‘physiological hunger’ or motiva-
tional drive to eat. Thus, by allowing each participant to choose
when they desire to eat, we are able to assess satiety as well as
motivational drive to eat. One caveat with this approach is making
sure the participants are blinded to all time cues to avoid request-
ing dinner based on environmental stimuli instead of physiological
cues. During the testing days, all windows were covered; watches,
wall-mounted clocks, and laptop clocks were removed; and cell
phones were turned off. In order to assess whether the participants
Fig. 4. Eating initiation as assessed from time to dinner request.
No snack (NS) vs.
All snacks, p< 0.05;
high protein (HP) vs. low protein (LP), p< 0.05;
à
HP vs.
moderate protein (MP), p< 0.05.
S.M. Douglas et al. / Appetite 60 (2013) 117–122 121
were aware of time cues, we asked them what time they thought it
was after they indicated they were ready to request dinner. The ac-
tual time of day and the participant-estimated time of day coin-
cided only 30% of the time. Therefore, it is reasonable to
conclude that the participants were effectively screened from all
time cues.
The main study limitation is the varying dietary and sensory
snack characteristics between the yogurt snacks outside of the dif-
fering quantities of dietary protein. As discussed in Sorensen,
Moller, et al. (2003), increased palatability, sweetness, and flavor
intensity consistently lead to increased food intake; however,
conflicting data exist with respect to their effects on appetite and
satiety. In the current study, we assessed perceptions of aroma,
flavor, texture, appearance, and palatability (like) for each yogurt.
Flavor was the only sensory component that differed between
yogurts. This only occurred between the MP vs. HP yogurt with
the MP yogurt characterized with weaker flavor vs. HP yogurt
(p< 0.05). When included in the mixed factor ANOVA, none of
these factors ended up remaining in the model as covariates.
Although the varying sensory characteristics appear to have mini-
mal effect on study outcomes, it is possible that the varying dietary
factors might have influenced the study findings. These include
dietary non-nutrients, fixed variables such as volume, mass, viscos-
ity, and energy density as well as the dietary nutrients, namely
macronutrient composition.
Foods and/or beverages of greater mass, volume, and/or viscos-
ity or lower energy density generally reduce appetite, increase sati-
ety, and/or reduce subsequent energy intake compared to high
energy-dense foods (see reviews (Rolls, 2009; Welch, 2011)). These
effects can be attributed to the increased amount of water and gas
infused into these foods and/or beverages (Welch, 2011). In our
current study, mass, volume, and energy density were similar be-
tween the low and moderate protein yogurts, whereas the high
protein yogurt exhibited a larger mass and volume but lower en-
ergy density. Because these differences might have substantially
contributed to the differences in perceived hunger, satiety, and
the onset of eating, caution is warranted when interpreting the
findings solely based on protein quantity of the afternoon snacks.
It is important to note, however, that a myriad of studies exist
examining the effects of high protein meals and/or diets and col-
lectively show reduce appetite, increase satiety, reduced onset of
eating, and reduce subsequent intake compared to low protein ver-
sions (Halton & Hu, 2004; Veldhorst et al., 2008; Westerterp-Plant-
enga et al., 2009). Although some argue that the effects shown with
increased dietary protein are primarily a result of the reduction in
carbohydrates and not the increase in protein, similar findings oc-
cur with high protein diets when carbohydrates are maintained
and dietary fat is reduced (Weigle et al., 2005).
In an attempt to assess the impact of the previously discussed
snack characteristics on the main study outcome, that being time
to dinner request, a multivariate, backward regression was per-
formed. Protein content and palatability of the snacks were the
only factors that significantly predicted the onset of eating,
accounting for 46.2% of the variability (p< 0.001).
In summary, we found that a 160 kcal afternoon Greek yogurt
snack, containing 24 g of protein, led to reduced afternoon appe-
tite, increased satiety, and delayed the onset of eating in healthy
women. These findings suggest that the daily incorporation of high
protein, afternoon snacks may prevent further snacking and poten-
tially overeating throughout the afternoon and evening hours.
References
Batterham, R. L., Heffron, H., et al. (2006). Critical role for peptide YY in protein-
mediated satiation and body-weight regulation. Cellular Metabolism, 4(3),
223–233.
Cummings, D. E., Frayo, R. S., et al. (2004). Plasma ghrelin levels and hunger scores
in humans initiating meals voluntarily without time- and food-related cues.
American Journal of Physiology-Endocrinology and Metabolism, 287(2), E297–304.
Dougkas, A., Minihane, A. M., et al. (2012). Differential effects of dairy snacks on
appetite, but not overall energy intake. British Journal of Nutrition, 1–12.
Halton, T. L., & Hu, F. B. (2004). The effects of high protein diets on thermogenesis,
satiety and weight loss. A critical review. Journal of the American College of
Nutrition, 23(5), 373–385.
Himaya, A., Fantino, M., et al. (1997). Satiety power of dietary fat. A new appraisal.
American Journal of Clinical Nutrition, 65(5), 1410–1418.
Holt, S. H., Miller, J. C., et al. (1995). A satiety index of common foods. European
Journal of Clinical Nutrition, 49(9), 675–690.
Johnson, G. H., & Anderson, G. H. (2010). Snacking definitions. Impact on
interpretation of the literature and dietary recommendations. Critical Reviews
in Food Science and Nutrition, 50(9), 848–871.
Leidy, H. J., Armstrong, C. L., et al. (2010). The influence of higher protein intake and
greater eating frequency on appetite control in overweight and obese men.
Obesity (Silver Spring), 18(9), 1725–1732.
Leidy, H. J., Carnell, N. S., et al. (2007). Higher protein intake preserves lean mass
and satiety with weight loss in pre-obese and obese women. Obesity (Silver
Spring), 15(2), 421–429.
Leidy, H. J., Lepping, R. J., et al. (2011). Neural responses to visual food stimuli after a
normal vs. higher protein breakfast in breakfast-skipping teens. A pilot fMRI
study. Obesity (Silver Spring), 19(10), 2019–2025.
Leidy, H. J., Mattes, R. D., et al. (2007). Effects of acute and chronic protein intake on
metabolism, appetite, and ghrelin during weight loss. Obesity, 15(5),
1215–1225.
Marmonier, C., Chapelot, D., et al. (2000). Effects of macronutrient content and
energy density of snacks consumed in a satiety state on the onset of the next
meal. Appetite, 34(2), 161–168.
Ortinau, L. C., Culp, J. M., et al. (2012). The effects of low versus higher protein
yogurt consumed as afternoon snacks on appetite control and time to dinner
request in healthy women. Experimental Biology, San Diego, CA; abstract 820.34.
Piernas, C., & Popkin, B. M. (2010). Snacking increased among US adults between
1977 and 2006. Journal of Nutrition, 140(2), 325–332.
Poppitt, S. D., Proctor, J., et al. (2011). Low-dose whey protein-enriched water
beverages alter satiety in a study of overweight women. Appetite, 56(2), 456–464.
Potier, M., Fromentin, G., et al. (2009). A high-protein, moderate-energy, regular
cheesy snack is energetically compensated in human subjects. British Journal of
Nutrition, 102(4), 625–631.
Rolls, B. J. (2009). The relationship between dietary energy density and energy
intake. Physiology & Behavior, 97(5), 609–615.
Skov, A. R., Toubro, S., et al. (1999). Randomized trial on protein vs. carbohydrate in
ad libitum fat reduced diet for the treatment of obesity. International Journal of
Obesity and Related Metabolic Disorders, 23(5), 528–536.
Sloan, A. E. (2009). The Pleasure Principle. Food Technology, 63(7).
Sloan, A. E. (2011). Top 10 Food Trends. Food Technology, 65(4).
Sorensen, L. B., Moller, P., et al. (2003). Effect of sensory perception of foods on
appetite and food intake. A review of studies on humans. International Journal of
Obesity and Related Metabolic Disorders, 27(10), 1152–1166.
Stachura, L. (2010). Snacking. Identifying a World of Opportunities For Dairy. from
<http://www.innovatewithdairy.com/Symposium/Documents/
2010%20Dairy%20Ingredients%20Symposium/stachura.pdf>.
The Nielsen Company, U. (2010). Greek Yogurt as a % of Total Yogurt Category.
USDA, (2011). Agricultural Research Service National Agricultural Library. Welcome
to the USDA National Nutrient Database for Standard Reference.
Veldhorst, M., Smeets, A., et al. (2008). Protein-induced satiety. Effects and
mechanisms of different proteins. Physiology & Behavior.
Weigle, D. S., Breen, P. A., et al. (2005). A high-protein diet induces sustained
reductions in appetite, ad libitum caloric intake, and body weight despite
compensatory changes in diurnal plasma leptin and ghrelin concentrations.
American Journal of Clinical Nutrition, 82(1), 41–48.
Welch, R. W. (2011). Satiety. Have we neglected dietary non-nutrients? Proceedings
of the Nutrition Society, 70(2), 145–154.
Westerterp-Plantenga, M. S., Nieuwenhuizen, A., et al. (2009). Dietary Protein,
Weight Loss, and Weight Maintenance. Annual Review of Nutrition.
122 S.M. Douglas et al. / Appetite 60 (2013) 117–122
... For example, although it has been shown that plain yogurt with high protein content (i.e., 24 g/160 kcal) caused increased satiety and delay in request for the next meal, (Douglas et al., 2013) plain yogurt with high protein to carbohydrate ratio (PCR 2.30, 23.1 g proteins/141 kcal) did not cause any differences in subjective satiety ratings compared to strawberry yogurt with low PCR (0.79, 18.3 g protein/167 kcal) (El Khoury et al., 2014). Beyond the small number of studies, research design such as yogurt consumption under energy-restricted diet or not; the study participants, high or low dairy consumers, men or women; the duration of the intervention, 12 weeks or higher; the type and the amount of yogurt, plain or fortified are parameters which significantly contribute to the variability which characterizes research results. ...
... Especially for yogurt, high-protein yogurt afternoon snacks have been shown to increase satiety compared to ones with lower protein content (Douglas et al., 2013;El Khoury et al., 2014) or to high-fat snacks such as crackers and chocolate (Ortinau et al., 2014) contributing to lower subsequent energy intake. However, when plain yogurt with high protein content (23.1 g proteins/141 kcal) was administered to healthy males, no differences in subjective satiety ratings were noticed compared to strawberry yogurt with low protein content (18.3 g protein/167 kcal) (El Khoury et al., 2014). ...
Article
Full-text available
Hunger-reducing effects and beneficial changes in gastrointestinal hormones have been reported, in overweight/obese individuals consuming dairy while yogurt takes pride of place due to its unique structure and composition. Although the contribution of yogurt to metabolic regulation has received growing attention, the research studies which examine its role on appetite are limited, especially regarding type 2 diabetes mellitus (T2DM) patients. The aim of the present study was to investigate the effects of non-fat, conventional yogurt consumption on appetite hormone responses of T2DM patients following a non-energy-restricted diet. Overweight subjects participated in a 12-week dietary intervention including 2 meals/day (2 × 200 g) of yogurt. At the beginning and the end of the intervention, a mixed meal tolerance test assessing the postprandial response of glucose, insulin, ghrelin, glucagon-like peptide-1 (GLP-1), and peptide-YY (PYY) was performed. Subjective appetite ratings were also evaluated. Area under the curve for glucose, insulin, ghrelin, GLP-1, and PYY responses did not differ after the 12-week intervention with yogurt (p > .05) as well as for subjective appetite ratings (p > .05). No significant differences were indicated at specific time points in any of the examined parameters. Regular consumption of non-fat, conventional yogurt for 12-week duration does not affect appetite hormone responses in overweight patients with T2DM following a non-energy-restricted diet.
... Currently, much research focuses on the development of enriched products with different protein sources to provide foods with high nutritional and functional properties and to counter protein deficiency, especially for kids and elderly people. Indeed, protein-enriched products could help the elderly to prevent chronic diseases and support the most vulnerable ones suffering from immunodeficiency, bone and muscle loss [6,7]. Protein-enriched products could thus improve quality of life and contribute to the establishment of a well-balanced diet especially considering the uptake of the essential amino acids [7]. ...
... Indeed, protein-enriched products could help the elderly to prevent chronic diseases and support the most vulnerable ones suffering from immunodeficiency, bone and muscle loss [6,7]. Protein-enriched products could thus improve quality of life and contribute to the establishment of a well-balanced diet especially considering the uptake of the essential amino acids [7]. Furthermore, a particular interest in enriching dairy products with proteins has been proven due to the relationship between proteins and ferments [8]. ...
Article
Full-text available
The aim of this study was to evaluate the effects of γ-irradiation (IR), ultrasound (US), and combined treatments of ultrasound followed by γ-irradiation (US-IR), ultrasound followed by enzymatic hydrolysis with and without centrifugation (US-E and US-EWC, respectively), and ultrasound followed by γ-irradiation and enzymatic hydrolysis (US-IRE), on the digestibility and the nutritional value of fermented beverages containing probiotics. Results showed that US (20 min), IR (3 kGy) and US-IR (tUS = 20 min, dose = 3 kGy) treatments raised protein solubility from 11.5 to 21.5, 24.3 and 29.9%, respectively. According to our results, these treatments were accompanied by the increased amount of total sulfhydryl groups, surface hydrophobicity and changes to the secondary structure of the proteins measured by Fourier-transform infrared spectroscopy (FTIR). Fermented probiotic beverages, non-enriched (C) and enriched with untreated (Cr) or treated cricket protein with combined treatments were also evaluated for their in vitro protein digestibility. Results showed that the soluble fraction of US-IRE fermented beverage had the highest digestibility (94%) as compared to the whole fermented tested beverages. The peptides profile demonstrated that US-IRE had a low proportion of high molecular weight (MW) peptides (0.7%) and the highest proportion of low MW peptides by over 80% as compared to the other treatments.
... In addition, the pre-VAS testing snack was not the same nor did we control energy intake prior to the snack. However, prior and similarly relevant studies did not control for these variables either [47,[73][74][75]. Nevertheless, future investigations should aim for stricter control protocols prior to VAS testing. ...
Article
Full-text available
(1) Background: The favorable effects of high protein snacks on body composition and appetite status in lean and athletic populations have been illustrated previously. However, the effects of soy-enriched high protein snacks have not been investigated in women with normal-weight obesity (NWO). Consequently, we aimed at comparing the effects of six months of soy-enriched high protein snack replacement on appetite, body composition, and dietary intake in women with NWO. (2) Methods: One hundred seven (107) women with NWO [(age: 24 ± 3 yrs, BMI: 22.7 ± 2.3 kg/m2, body fat percentage (BFP): 38 ± 3.2%)] who were assigned to one of two groups; high protein snack (HP, n = 52) containing 50 g soybean or isocaloric low-protein snack (protein: 18.2 g, carbohydrate: 15 g, fat: 10 g, energy: 210 kcal) or isocaloric low protein snack (LP, n = 55) containing 3.5 servings of fruit (protein:
... Esta fortificación de proteínas puede realizarse antes o después de la fermentación tanto con un concentrado de proteína de leche (MPC) (18) como con un concentrado micelar de caseína (MCC) (19) o un concentrado de proteína del suero de leche (WPC) (20), que alterarán sus propiedades nutricionales y organolépticas. Interesantemente, la ingesta de estos productos, que debido a su mayor aporte proteico son también ricos en calcio y péptidos bioactivos, se ha asociado a una disminución del apetito y a un incremento de la saciedad cuando se compara con la de los yogures batidos, de menor contenido proteico (21,22). Por ello pueden incluirse como alternativa a los snacks, con mejor contenido nutricional, por ejemplo en las poblaciones que busquen controlar el peso corporal. ...
Article
Full-text available
Introducción: la proteína es un nutriente esencial que se puede obtener a través de diferentes fuentes alimentarias . En los últimos años, un creciente desarrollo de la industria alimentaria de productos lácteos con mayor aporte en proteínas ha surgido en el mercado nacional. Métodos: el presente trabajo analizó la información nutricional, el contenido proteico y el perfil de aminoácidos de una serie de yogures altos en proteína. Se seleccionaron 5 principales marcas de yogures altos en proteína (YP), una muestra de yogur batido (YBAT) y una de proteína de suero de leche aislado (WP) a las que se realizó un análisis proximal y un perfil de aminoácidos por cromatografía líquida de alta resolución (HPLC). Resultados: se pudo observar que el contenido de proteína de los YP analizados varió entre 7,2-15,1 g/porción, lo que representa del 6,8 al 11 % del contenido total, el doble del contenido del YBAT (3,4 %). Respecto a los hidratos de carbono y grasas, estos se encontraron entre 6,25 y 13,5 g/porción y 0,9 y 5,3 g/porción, respectivamente. El contenido de leucina de los YP varió entre 0,6 y 1,5 g/porción, con valores superiores a los de los YBAT (0,3 g/porción) e inferiores a los de las WP (2,2 g/porción). La suma de aminoácidos esenciales de se encontró entre 3 y 6,9 g/porción en los YP, en 1,7 en los YBAT y en 8,5 en las WP. Conclusión: Estos resultados demuestran que los YP son una buena alternativa para promover una correcta ingesta proteica, semejante a las proteínas de uso deportivo, por lo que su recomendación podría ser útil para promover su consumo en diferentes poblaciones según sus necesidades.
... Esta fortificación de proteínas puede realizarse antes o después de la fermentación tanto con un concentrado de proteína de leche (MPC) (18) como con un concentrado micelar de caseína (MCC) (19) o un concentrado de proteína del suero de leche (WPC) (20), que alterarán sus propiedades nutricionales y organolépticas. Interesantemente, la ingesta de estos productos, que debido a su mayor aporte proteico son también ricos en calcio y péptidos bioactivos, se ha asociado a una disminución del apetito y a un incremento de la saciedad cuando se compara con la de los yogures batidos, de menor contenido proteico (21,22). Por ello pueden incluirse como alternativa a los snacks, con mejor contenido nutricional, por ejemplo en las poblaciones que busquen controlar el peso corporal. ...
Article
Full-text available
Introduction: protein is an essential nutrient that can be obtained through different food sources. In recent years, a growing development in the food industry of dairy products with higher protein content has emerged in the national market. Métodos: the present work analyzed the nutritional information, protein content, and amino acid profile of high protein yogurts. Five main brands of high-protein yogurt (PY) were selected, as was a sample of regular yogurt (RY), and one of whey protein isolate (WP), which underwent a proximal analysis and amino acid profile by high-performance liquid chromatography (HPLC). Results: it was observed that the protein content of the analyzed YP ranged between 7.2 and 15.1 g/portion, representing 6.8 % to 11 % of total content, twice the content of YBAT (3,4 %). Regarding carbohydrates and fats, these were found to range between 6.25 and 13.5 g/serving and 0.9 and 5.3 g/serving, respectively. Leucine content of the PY varied between 0.6 and 1.5 g/portion, which was higher than RY (0.3 g/portion) and lower than WP (2.2 g/portion). The sum of essential amino acids was found to be between 3 and 6.9 g/portion in PY, 1.7 in PY, and 8.5 in WP. Discussion: these results show that PYs are a good alternative to promote a correct protein intake, similar to proteins for sports use, so their recommendation could be useful to promote consumption in different populations according to their needs.
... Several studies have also found that consuming yogurt as a snack, whether low or rich in protein, enhanced feelings of satiety, increased feelings of fullness, and delayed dinner for a long period of time [ 189 ,190 ]. Douglas et al. [190] conducted a study on healthy women who were served Greek yogurt, containing 24 g of protein and found that it enhanced their feeling of satiety. Dougkas [191] compared milk and cheese to yogurt and found that while yogurt was better at suppressing appetites, it did not affect subsequent food intake. ...
Article
Full-text available
Eating outside the three main meals – in other words, snacking – is a part of the dietary pattern of individuals in all stages of life. The quality and pattern of snacking have an impact on health during the life span. Thus, the aim of this review was to evaluate various patterns and health outcomes of the snacking habits of different demographical groups, from children to the elderly, throughout their life span. We discuss the snacking pattern among children and adolescents, which is characterized by consuming high energy foods with low nutrient value, and which is associated with increased risk of obesity. During university years, study stress and lack of time were obstacles to a healthy dietary pattern involving nutritious snacks, although awareness of the importance of healthy snacks was higher in this group than among younger age groups. Employment status and skipping regular meals were important factors affecting snacking quality and patterns in adulthood. Unhealthy snacks, high in energy, sugar, and salt and low in nutrients, were demonstrated to have a negative impact on individuals' health, such as oral health, blood pressure, obesity, and diabetes. In conclusion, encouraging individuals to consume healthy snacks that are high in nutrients through education to help them plan for their snacks is important to enhance health and reduce disease risk.
Article
The present study aimed to assess the impact of daily consumption of a snack fortified with plant proteins with high content in amino acids with appetite regulating properties (BCAAs and L-arginine), as part of a dietary intervention, on weight loss. Seventy adults without diabetes (26 male, 44 female) and with overweight/obesity participated in a 12-week restricted dietary intervention and were randomized to either a control or an intervention group, consuming daily 70 g of conventional wheat biscuits (CB) or an isocaloric amount of wheat biscuits enriched with plant proteins (PB) originating from legumes and seeds, respectively. Anthropometric characteristics were measured and venous blood samples were collected at baseline and at the end of the intervention. Decreases in body weight, body fat mass and waist circumference were observed in both groups. Participants in the intervention group experienced greater weight loss (7.6 ± 2.7 vs. 6.2 ± 2.7%, p = 0.025) and marginally significant larger decrease in body fat mass (4.9 ± 2.2 vs. 3.9 ± 2.4 kg, p = 0.059). A moderate reduction in IL-1β levels (p = 0.081), a significantly higher decrease in TNF-α levels (p < 0.001) and a marginally significant greater leptin decrease (p = 0.066) in subjects of the PB group were noticed. Greater reductions in caloric and carbohydrate intake and a trend towards a higher decrease in fat intake were also observed in participants of this group. Incorporation of plant-based proteins with high content in amino acids with appetite-regulating properties in wheat biscuits may contribute to greater weight loss and improvement of metabolic parameters in subjects who are overweight or obese. Protein enrichment of snacks offers a beneficial qualitative manipulation that could be successfully incorporated in a diet plan.
Article
Yogurt is a fermented milk product characterised by a peculiar nutritional composition with live and viable cultures of bacteria. Few studies have analysed the benefits of yogurt consumption on health outcomes during paediatric age. Recent epidemiological studies evaluating the nutritional impact of yogurt have demonstrated its significant contribution to nutrients intakes among children. Thus, consuming yogurt is a strategy to achieve recommended nutrient intake and healthier dietary choices, with potential impact on obesity and cardiometabolic outcome in children. Yogurt's effects on paediatric infectious diseases, gastrointestinal diseases and atopic-related disorders are ascribed to the specific probiotic strain administered. Interestingly, the benefits of yogurt consumption are most likely due to effects mediated through the gut microbiota and the enhancement of innate and adaptive immune responses. Therefore, supplementing standard yogurt cultures with probiotic strains could be useful to promote health at different paediatric ages, although more evidence is needed regarding the strain-related effects and their interplay within the paediatric immune system.
Article
Aim: High-protein diets are considered as useful diets for weight loss programs. We collected randomized controlled trials that evaluated the effect of protein on appetite and gastrointestinal hormones involved in appetite regulation. Methods: Trials were included if participants were healthy adults and isocaloric treatments were used in control and treatment arms. Random-effects model was used to calculate mean difference and 95% confidence intervals. Results: In total, 49 publications for acute and 19 articles for long-term effect of protein were included. In acute interventions, protein decreased hunger (-7 mm visual analogue scale (VAS), P<0.001), desire to eat (-5 mm, P=0.045), and prospective food consumption (-5 mm, P=0.001) and increased fullness (10 mm, P<0.001) and satiety (4 mm, P<0.001). There was also a decrease in ghrelin (-20 pg/ml, P<0.001) and increase in cholecystokinin (30 pg/ml, P<0.001) and glucagon-like peptide-1 (GLP-1) (21 ng/ml, P<0.001), but no change in gastric inhibitory polypeptide and peptide YY was observed. Appetite markers were affected by protein doses < 35 g but ghrelin, cholecystokinin, and GLP-1 changed significantly after doses ≥ 35 g. Long-term ingestion of protein did not affect these outcomes, except for GLP-1 which showed a significant decrease. Conclusion: Results of this meta-analysis showed that acute ingestion of protein suppresses appetite, decreases ghrelin, and augments cholecystokinin and GLP-1. Results of long-term trials are inconclusive and further trials are required before a clear and sound conclusion on these trials could be made.
Conference Paper
Full-text available
Dietary regulation of appetite may contribute to the prevention and management of excess body weight. The present study examined the effect of consumption of individual dairy products as snacks on appetite and subsequent ad libitum lunch energy intake. In a randomised cross-over trial, forty overweight men (age 32 (sd 9) years; BMI 27 (sd 2) kg/m2) attended four sessions 1 week apart and received three isoenergetic (841 kJ) and isovolumetric (410 ml) servings of dairy snacks or water (control) 120 min after breakfast. Appetite profile was determined throughout the morning and ad libitum energy intake was assessed 90 min after the intake of snacks. Concentrations of amino acids, glucose, insulin, ghrelin and peptide tyrosine tyrosine were measured at baseline (0 min) and 80 min after the intake of snacks. Although the results showed that yogurt had the greatest suppressive effect on appetite, this could be confounded by the poor sensory ratings of yogurt. Hunger rating was 8, 10 and 24 % (P < 0·001) lower after the intake of yogurt than cheese, milk and water, respectively. Energy intake was 11, 9 and 12 % (P < 0·02) lower after the intake of yogurt, cheese and milk, respectively, compared with water (4312 (se 226) kJ). Although there was no difference in the postprandial responses of hormones, alanine and isoleucine concentrations were higher after the intake of yogurt than cheese and milk (P < 0·05). In conclusion, all dairy snacks reduced appetite and lunch intake compared with water. Yogurt had the greatest effect on suppressing subjective appetite ratings, but did not affect subsequent food intake compared with milk or cheese.
Article
Background: Ad libitum, low-carbohydrate diets decrease caloric intake and cause weight loss. It is unclear whether these effects are due to the reduced carbohydrate content of such diets or to their associated increase in protein intake. Objective: We tested the hypothesis that increasing the protein content while maintaining the carbohydrate content of the diet lowers body weight by decreasing appetite and spontaneous caloric intake. Design: Appetite, caloric intake, body weight, and fat mass were measured in 19 subjects placed sequentially on the following diets: a weight-maintaining diet (15% protein, 35% fat, and 50% carbohydrate) for 2 wk, an isocaloric diet (30% protein, 20% fat, and 50% carbohydrate) for 2 wk, and an ad libitum diet (30% protein, 20% fat, and 50% carbohydrate) for 12 wk. Blood was sampled frequently at the end of each diet phase to measure the area under the plasma concentration versus time curve (AUC) for insulin, leptin, and ghrelin. Results: Satiety was markedly increased with the isocaloric high-protein diet despite an unchanged leptin AUC. Mean (±SE) spontaneous energy intake decreased by 441 ± 63 kcal/d, body weight decreased by 4.9 ± 0.5 kg, and fat mass decreased by 3.7 ± 0.4 kg with the ad libitum, high-protein diet, despite a significantly decreased leptin AUC and increased ghrelin AUC. Conclusions: An increase in dietary protein from 15% to 30% of energy at a constant carbohydrate intake produces a sustained decrease in ad libitum caloric intake that may be mediated by increased central nervous system leptin sensitivity and results in significant weight loss. This anorexic effect of protein may contribute to the weight loss produced by low-carbohydrate diets.
Article
Dietary regulation of appetite may contribute to the prevention and management of excess body weight. The present study examined the effect of consumption of individual dairy products as snacks on appetite and subsequent ad libitum lunch energy intake. In a randomised cross-over trial, forty overweight men (age 32 (sd 9) years; BMI 27 (sd 2) kg/m2) attended four sessions 1 week apart and received three isoenergetic (841 kJ) and isovolumetric (410 ml) servings of dairy snacks or water (control) 120 min after breakfast. Appetite profile was determined throughout the morning and ad libitum energy intake was assessed 90 min after the intake of snacks. Concentrations of amino acids, glucose, insulin, ghrelin and peptide tyrosine tyrosine were measured at baseline (0 min) and 80 min after the intake of snacks. Although the results showed that yogurt had the greatest suppressive effect on appetite, this could be confounded by the poor sensory ratings of yogurt. Hunger rating was 8, 10 and 24 % (P < 0·001) lower after the intake of yogurt than cheese, milk and water, respectively. Energy intake was 11, 9 and 12 % (P < 0·02) lower after the intake of yogurt, cheese and milk, respectively, compared with water (4312 (se 226) kJ). Although there was no difference in the postprandial responses of hormones, alanine and isoleucine concentrations were higher after the intake of yogurt than cheese and milk (P < 0·05). In conclusion, all dairy snacks reduced appetite and lunch intake compared with water. Yogurt had the greatest effect on suppressing subjective appetite ratings, but did not affect subsequent food intake compared with milk or cheese.
Article
The consumer food products industry has witnessed significant growth of sales in the year 2010 and is expected to increase in the year 2011. Supermarkets continue to dominate consumer food spending with a 49% share of sales in 2010. Households with incomes of less than $35,000 are projected to represent nearly 40% of the US households by 2015. Low-income households are expected to deliver $115 billion in incremental consumer packaged goods (CPG) spending in future. Low-income shoppers are driving growth in fresh bread/rolls, yogurt, salty snacks, natural cheese, and cold cereal, among other sectors. Affluent ethnic households, which represent $110 billion in purchasing power, are another overlooked market segment. Sales of foods/drinks formulated without preservatives topped $14.5 billion in 2009, sales of products with a natural claim reached $22 billion. Consumers are moving toward products that are naturally high in vitamins/minerals and those that have been blended with other foods to create even higher nutrient levels.
Article
Much of the research in ingestive behavior has focused on the macronutrient composition of foods; however, these studies are incomplete, or could be misleading, if they do not consider the energy density (ED) of the diet under investigation. Lowering the ED (kcal/g) by increasing the volume of preloads without changing macronutrient content can enhance satiety and reduce subsequent energy intake at a meal. Ad libitum intake or satiation has also been shown to be influenced by ED when the proportions of macronutrients are constant. Since people tend to eat a consistent weight of food, when the ED of the available foods is reduced, energy intake is reduced. The effects of ED have been seen in adults of different weight status, sex, and behavioral characteristics, as well as in 3- to 5-year-old children. The mechanisms underlying the response to variations in ED are not yet well understood and data from controlled studies lasting more than several days are limited. However, both population-based studies and long-term clinical trials indicate that the effects of dietary ED can be persistent. Several clinical trials have shown that reducing the ED of the diet by the addition of water-rich foods such as fruits and vegetables was associated with substantial weight loss even when patients were not told to restrict calories. Since lowering dietary energy density could provide effective strategies for the prevention and treatment of obesity, there is a need for more studies of mechanisms underlying the effect and ways to apply these findings.
Article
This functional magnetic resonance imaging (fMRI) pilot study identified whether breakfast consumption would alter the neural activity in brain regions associated with food motivation and reward in overweight "breakfast skipping" (BS) adolescent girls and examined whether increased protein at breakfast would lead to additional alterations. Ten girls (Age: 15 ± 1 years; BMI percentile 93 ± 1%; BS 5 ± 1×/week) completed 3 testing days. Following the BS day, the participants were provided with, in randomized order, normal protein (NP; 18 ± 1 g protein) or higher protein (HP; 50 ± 1 g protein) breakfast meals to consume at home for 6 days. On day 7 of each pattern, the participants came to the laboratory to consume their respective breakfast followed by appetite questionnaires and an fMRI brain scan to identify brain activation responses to viewing food vs. nonfood images prior to lunch. Breakfast consumption led to enduring (i.e., 3-h post breakfast) reductions in neural activation in the hippocampus, amygdala, cingulate, and parahippocampus vs. BS. HP led to enduring reductions in insula and middle prefrontal cortex activation vs. NP. Hippocampal, amygdala, cingulate, and insular activations were correlated with appetite and inversely correlated with satiety. In summary, the addition of breakfast led to alterations in brain activation in regions previously associated with food motivation and reward with additional alterations following the higher-protein breakfast. These data suggest that increased dietary protein at breakfast might be a beneficial strategy to reduce reward-driven eating behavior in overweight teen girls. Due to the small sample size, caution is warranted when interpreting these preliminary findings.
Article
Satiety, which is the inhibition of eating following the end of a meal, is influenced by a number of food characteristics, including compositional and structural factors. An increased understanding of these factors and the mechanisms whereby they exert their effects on satiety may offer a food-based approach to weight management. Water and gas, which are often neglected in nutrition, are major components of many foods and contribute to volume, and to sensory and other characteristics. A review of previous short-term studies that evaluated the effects of water or gas in foods on satiety showed that while satiety was generally increased, effects on subsequent intakes were not always apparent. These studies were diverse in terms of design, timings and food matrices, which precludes definitive conclusions. However, the results indicate that solids may be more effective at increasing satiety than liquids, but gas may be as effective as water. Although increased gastric distension may be the main mechanism underlying these effects, pre-ingestive and ingestive impacts on cognitive, anticipatory and sensory responses also appear to be involved. Furthermore, there is limited evidence that water on its own may be effective at increasing satiety and decreasing intakes when drunk before, but not with, a meal. Longer-term extrapolation suggests that increasing food volumes with water or gas may offer weight-management strategies. However, from a practical viewpoint, the effects of water and gas on satiety may be best exploited by using these non-nutrients to manipulate perceived portion sizes, without increasing energy contents.